Reducing overselective stimulus control with differential observing responses

Farber and team worked with 19 students in a classroom.

They added a quick identity-matching step inside delayed matching-to-sample trials.

Kids had to pick the exact sample again before the real choice. This extra look is called a differential observing response, or DOR.

Sixteen students started picking the right comparison more often after the DOR was added.

When the extra step was slowly taken away, most kids still matched correctly.

The brief self-check helped them notice all parts of the picture instead of zoning in on just one piece.

Reynolds et al. (2011) also fought over-selectivity, but they kept the same reward schedule instead of adding a response. Both tactics widened stimulus control, so you now have two levers: steady pay or an extra look.

Ribeiro et al. (2024) tucked a quick math problem into the same delay window. Their college students built bigger equivalence classes, while Farber’s kids just aimed better. Same spot, different jobs — proof the pause can be loaded for many goals.

Arntzen et al. (2015) simply stretched the delay to six seconds and saw big gains too. Farber shows you don’t need more wait time; you need something meaningful to do during the wait.

If a learner keeps picking the wrong card even after repeated trials, slide in a one-second identity check. Ask them to touch the sample again before you show the choices. It costs no extra materials and often fixes the error pattern in the same session. Try it next time over-selectivity pops up.